Method of making low-density coked products.



HUGH BODMAN, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR '10 RODMAN CHEMICALCOMPANY, A CORPORATION OF PENNSYLVANIA.

Be it known that I, HUGH RODMAN, a citizen of the United States, and aresident of I Edgewood, in the county of Allegheny and State ofPennsylvania, have made a new and useful Invention in Methods of MakingLow- Density Coked Products, of which the following is a specification.

This invention relates to the production of low density coked productsand discloses a new and improved method of making such products.

Efforts have been made to make low density products by heating a cokingmaterial or a mixture containing coking material in such a way as toproduce masses of light, porous coked material, these masses beinggenerally crushed and screened to ob tain the size of product desired.As this process is articularly applicable to the production ofcarburizing material, I will de scribe it in that connection, though theart is also applicable to the production of filter inimaterial, fillingfor reaction towers, etc.

imiting the description further to the use of a single coking material,I will describe a process which I have used commercially for theproduction of light, coked, carburizing material and then describe thenew and improved process forming the basis of this patent application,

I have hitherto made light, coked carburizing material by mixing a massof finely powdered coking coal with powdered energizers, such as limeand soda ash, and then feeding this mixture into a heated revolving kilnso that the mixture was coked while tumbling. In this way I haveproduced excellent carburizing material, but in general have found greatdifliculty in regulating the operation so as to avoid the production ofdust and oversized material. The object aimed at was the production oflight coked masses about one quarter inch in diameter, but there wouldalways be considerable material in lump larger than desired and alsoconsiderable small material and dust. The

oversize lump could of course be crushed to proper size, but in doing somore dust was produced, and the dust was generally waste or requiredfurther, expensive treatment.

' My present inventionlis a process of-. making such light cokedproducts practically Specification of Letters Patent.

Patented Oct. 29, 1918.

Application filed February 7, 1917. Serial No. 147,099.

without waste and in a way that allows of great flexibility both inmanufacturing and 1n the character of product produced. That is, itgives a means of maklng the material without the production of dust andalso makes it possible and easy to produce material of any densitydesired. It also produces an improved light coked product in that thefinished roduct has a comparatively smooth sur ace, differing from theedged and angular product obtained by crushing, and therefore lessliable to produce dust in handling. It also makes possible theproduction of a very uniformly sized product, as the material, in thisnew process, is sized before being coked, and the uncoked oversize andundersize material can be easily manipulated to produce propersizeduncoked material; in this Way avoiding all Waste.

The new process consists in forming the raw material into pellets 0'fragments of proper size and so made that hey will, when heated quickly,expand in size, or at least not contract, and coke to a firm material ofthe size desired without breaking up or adhering to neighboringfragments and without producing any considerable dust.

Before describing the process further, I will explain that I havehitherto made carburizing material by fashioning coking material, or amixture containing coking material, into pellets or fragments and havethen coked them, either before or during use as a carburizing agent, toproduce small unit masses of coked material. This old process differsfrom the present one in that the pellets or fragments produced were ofsuch construction and coked in such a way that the resultant cokedproduct generally occupied a much smaller volume after coking thanbefore. In other words, each small fragment or pellet would shrink involume durin the coking process till it occupied rough? 60% to of itsoriginal raw volume; and the final product was therefore, generallydense and heavy.

I now find that by coking the pellets or fragments as originally made,but much more rapidly than was customary, and also by changing theformula of the mixture and then coking rapidly, I can cause eachindividual pellet or fragment to expand in size B during the cokingprocess, instead of shrinking as heretofore, and at the same time causeit to substantially maintain its original contour. In this way I roduceexcellent carburizing material of ow density and without waste.

As a concrete example I will state that I have heretofore made pelletsorfragments by fashioning a mixture of one hundred parts finely powderedcoking coal, ten parts of soda ash and fifteen parts of lime, usin amolasses solution as binding agent, an generally tumbling the materialto produce small pellets or pills about one-fourth inch in diameter.These were sometimes dried by entle heat and then used direct as a car-%urizing agent, or they were sometimes fed into the cold end of arotating kiln and gradually dried and coked and discharged at the hotend. In either case there was a loss in wei ht of about 35% (due to thevaporizing o the water, loss of gas by the coal and reduction of thelime and soda ash) and also a loss in volume of about 35%. The netresult was the roduction of raw pills with a density of a out 7 O(figuring water as 100 dense), when measure in coking, lost 35% involume and 35% 1n weight, leaving finally a coked product having 65% theoriginal weight and still having a density of 7 (The denslty is that ofa pile of pellets rather than of a single pellet; that is, a pint of thepellets weighed 70% of the weight of a pint of water). 85 In carr ingout the new process I first dry the pills (if that be necessary) andthen heat them very rapidly, generally agitating them at the sametime'to destroy any light adhesions. In this way I am able to overcomethe excessive shrinkage of the old method, and instead of the pelletslosing volume they either hold their original volume or else increase involume, so that by this new process I can easily make a product with adensity of 30 and can vary the density to produce lighter or heavierpellets as desired. The new process of coking very rapidly can beapplied to the pellets as formerly compounded, but I prefer to make thepellets for this new process with a weaker bond than before. tion areused there is a setting or hardening effect due to the reaction of thesetwo materials, so that in coking the expanding force of the. ent ingases has to overcome this strong ond. For this reason I prefer to usepowdered marble dust instead of lime" with molasses solution and to usea weaker solution of molasses. As an improvement beyond this, I mayprefer to use a binding agent having considerable value as a cokeproducer and I find ordinary tar will serve excellently. I may make thepellets by tumbling the mixture of powdered coal, limeel stone and sodaash (as 100 parts of coal, 10

d in bulk, which,

, broader than these limitations. I have also When lime and molassessoluparts of soda ash and 15 parts of limestone) with liquid tar so asto fashion small pellets or pills; these are screened to secure thesizes desired andthen fed into arevolving furnace or kiln maintained atabout 1500 F. The volatile matter from the tar and the coal burn abovethe tumbling mass and maintain, or help to maintain, the propertemperature and the individual pellets are coked quickly, expanding asbefore described, and finally discharging into a cooling device. Theform of the heating devices for coking the pellets rapidly forms no partof this invention, but I. find a satisfactory device to consist of arotating furnace so arranged that the incoming pellets fall directlyinto a considerable mass of tumbling pellets already coked and hot. Ican accomplish the same purpose of coking rapidly by feeding the pelletsinto an ordinary rotary kiln, taking care to see that they quickly reacha coking zone; that is, the ordinary cold, feed end of the kiln ismaintained at or near acoking temperature.

I have described one method of making thepellets or fragments, onemixture, one device for coking, etc., and also one objectthe productionof light carburizing material, but I conceive of my invention as spokenof the pellets increasing in volume or at least not shrinking. It willbe apparent that they might be compounded or manipulated so as to shrinkslightly and still mark an advance over the excessive. shrinkage of theold processes.

I have also spoken of tar and its coking properties, but it will beapparent to those skilled in such matters, that other coking materials,aS heavy oil or heav molasses may be used. Also the total co ingmaterial in .the raw pellet or fragment may be the binder, as the tar,the rest of the carbonaceous material in the pellet being non-coking, ascharcoal dust; r

What I claim is:

'1. The process of making. low density products which consists infashioning coking material ora mixture containing coking material intopellets or fragments and abruptly subjecting the fragments to a cokingtemperature.

2, The process of making low density carburizing materiahwhich consistsin manipulating fine material with a coking binder to produce ellets orfragments and then cokmg rapi y by initially subjecting the pelletsorfragments to a coking temperaure. Q

3. 'The process of making low density products, which' consists inmanipulating fine material with a tarry binder to produce pdelllets orfragments and then coking rap- 4. The process of making low density"coking coal, or a mixture 1,283,310 I lit products, which consists infashioning fine, containing fine cokingcoal, into pellets or fragmentsand then coking rapidly, by initially subjecting the pellets orfragments to a coking temperature.

5. The process of making low density products, which consists infashioning a coking material or a mixture containing coking materialinto pellets or fragments, the bonding agent of which will not stronglyresist disrupting by heat and" then coking rapidly.

6. The process of making carburizing material of low density, whichconsists in fashioning a coking material or a mixture containing cokingmaterial into pellets or fragments and-then expanding them by asubstantially abrupt application of a coking eat.

7. The process of making low density products which consists infashioning coking material or a mixture containing coking material intopellets or fragments, and rapidly coking the same by initiallysubjecting them to a tumbling or agitated mass of hot previously cokedpellets or fragments maintained at a coking temperature.

In testimony whereof I havehereunto subscrlbed my name this 2nd day ofFebruary, 1917.

HUGH RODMAN,

